This invention relates to automotive wiring harness grommets and more particularly to a compound-molded grommet which is useful in protecting an automotive wiring harness where it passes through an aperture in a metal structure such as an A pillar as well as providing a sound deadening function to prevent the transmission of noise and vibrations through the automotive body.
Wiring harnesses of different sizes are used in automobiles to service various electronic components which pass through body structures such as firewalls and pillars. To protect the wiring harness from chafing and to close the aperture through which the harness passes, it is common to use grommets of rubber or elastomeric material. Within the context of this application, the term xe2x80x9cgrommetxe2x80x9d is defined as a structure which serves as a fastening, support or reinforcement and is made of a moldable material such as plastic which is suitable to protect a wiring harness or bundle passing therethrough.
Grommets are typically made of a single material such as plastic or rubber and may be provided with peripheral slots or channels for attachment to a surrounding structure. Grommets made in several parts are shown in U.S. Pat. Nos. 5,545,854 and 5,736,677, assigned to Yazaki Corporation of Tokyo, Japan.
The present invention provides an improved grommet for the securement and protection of automotive wiring harnesses or bundles with the further objective of providing convenient places for secure attachment of the harness or bundle to the front and rear of the grommet. In general, the objectives of the invention are achieved by constructing an integral grommet made by compound or serial molding from two materials; i.e., a relatively rigid plastic such as polypropylene is used to make a core element, and a thermoplastic elastomer such as Santoprene(copyright) molded over the core element in such a way as to fully enclose most of the core, leaving forwardly and rearwardly extending attachment tabs exposed. The harness or bundle may, upon installation, be attached to the tabs both in front of and behind the grommet.
In the preferred and illustrative embodiment, the body portion is designed as a frame with interior openings to reduce the quantity of material needed and with a side opening or slot to receive a wiring harness therein. The elastomeric overmold is designed to provide a harness receiving tube which is aligned with the side opening slot which tube extends in the forward direction adjacent and over a forwardly extending attachment tab. The tube in the overmold is split, either in the original molding process or in a secondary operation, so that the wiring harness can be slipped into the grommet before the grommet is attached to a metal structure designed to receive it. The elastomeric overmold has a soft, pliable, peripheral lip on the interior side to lie against a surface of the metal structure. Top and bottom slots or undercuts hold the grommet in place.